By Loz Blain May 27, 2021 Source New Atlas
New York City startup Kelekona is proposing a mass transport-sized eVTOL air bus service capable of carrying 40 people long distancesKelekona / rabbit75_dep/Depositphotos View 3 Images
Most eVTOL companies are thinking at air taxi scale, offering just 2-5 seats. Lilium is a notable exception, putting forth a whopping 7-seat “air minibus” design and prioritizing longer trips. But there are very few companies thinking at the kind of scale Kelekona’s talking about.
This audacious New York City startup is thinking in terms of 40 passengers plus a pilot per flight – or an enormous 10,000 lb (4,540 kg) of cargo. And apparently long distances and high speeds, too, since the Kelekona website promises these VTOL sky buses will make the 330-mile (531 km) run between LA and San Francisco in just one hour.
The airframe is certainly an interesting design. It’ll rise off the ground in VTOL operations using four banks of two large, ducted fans with variable pitch blades. These fan banks will tilt forward to get this giant bird moving into forward flight – but where most vectored thrust eVTOLs have large, wide wings, Kelekona plans to rely on the body shape alone to provide enough lift for efficient forward flight.
Thus, it’s got a chunky, flat, wide body with a mild teardrop shape to its side profile. The front is rounded, the rear end tapered. The bottom looks pretty flat, and the top is slightly domed to turn the whole blobby thing into a lifting surface.
The look is bizarre and a little blimpy, and we’re fascinated to learn how the aerodynamics will work out. Surely it’ll have to be moving pretty damn fast to support itself in the sky carrying 40 people and the kind of colossal battery bank you’ll need for inter-city flights.
Charging those puppies will be no trivial matter, either; we must be talking about several megawatt-hours’ worth of high-density lithium batteries here. Plug it into a wall socket and you might be ready to fly the thing back to home base in a few weeks. Thus Kelekona is planning to make the entire battery pack swappable, rolling the whole underfloor of the aircraft out to be slow-charged while the big sky bus moves on to its next destination.
The only other similar eVTOL mass transit project that springs to mind is Britain’s GKN Aerospace with its Skybus aircraft, which proposes offering 30-50 seats on cross-town vertical commutes. But GKN is planning to use two enormous connected wings to get the job done. The advantages and disadvantages are immediately clear; the GKN design will produce a lot more lift, flying much more efficiently at slower speeds, but with 50 seats in its cabin it may well be as wide as a 747. Finding space to safely launch and land these things in city areas won’t be easy.
The Kelekona design, on the other hand, might be able to operate off something 3-4 times the size of a regular helipad. Still challenging to make space for in an urban environment, but easier than if it had a couple hundred feet of wingspan to think about. It’s going to have to fly fast and far to operate efficiently, though, and that means its energy requirements will be absolutely epic.
It’s a fascinating and different proposition that seems aerodynamically improbable and energetically even harder. We’ve lined up a chat with the founder to talk it through, and will bring you more on this extremely odd aircraft in the coming days.
Check out a render video below. https://www.youtube.com/embed/dV91vXU4YHk?enablejsapi=1 A different class of eVTOL